Ships hoisting gear for heavy loads

ABSTRACT

The invention provides a ship&#39;&#39;s hoisting gear for heavy loads, in the form of twin booms or derricks stayed from a mast for luffing and slewing and cooperating to hoist a common lifting beam carrying a load. The gear comprises an auxiliary luffing boom between the two booms or derricks, and hoisting ropes which are taken from the booms or derricks over pulleys on said lifting beam to the head of the auxiliary luffing boom to which their ends are anchored.

United States Patent lnventor Hans Thaeter Bremen, Germany Appl. No. 786,625

Filed Dec. 24, 1968 Patented Jan. 26, 1971 Assignee Atlas-MaK Maschinenbau G.m.b.H.

Kiel-Friedrichsort, Germany a firm Priority Jan. 19, 1968 Germany A29083 SHIPS HOISTING GEAR FOR HEAVY LOADS 3 Claims, 2 Drawing Figs.

U.S. Cl 212/58, 212/3, 212/144 Int. Cl B66c 23/00 Field of Search 212/3, 58, 59, 47, l 144 [5 6] References Cited UNITED STATES PATENTS 3,245,549 4/1966 Trevisan 212/3 3,446,362 5/1969 Banks 212/3 Primary Examinerl-larvey C. Hornsby Att0rneyLowry, Rinehart & Markva ABSTRACT: The invention provides a ships hoisting gear for heavy loads, in the form of twin booms or derricks stayed from a mast for luffing and slewing and cooperating to hoist a common lifting beam carrying a load. The gear comprises an auxiliary luffing boom between the two booms or derricks, and hoisting ropes which are taken from the booms or derricks over pulleys on said lifting beam to the head of the auxiliary luffing boom to which their ends are anchored.

SHIPS HOISTING GEAR FOR HEAVY LOADS BACKGROUND OF THE INVENTION This invention relates to ships hoisting gear for heavy loads, in the form of twin booms or derricks stayed from a mast for luffing and slewing and cooperating to hoist a common lifting beam carrying a load.

Two booms or twin derricks are a common form of hoisting gear on ships, each boom or derrick being available for hoisting light loads, whereas both booms or derricks together are also operable in parallel for lifting a heavy load attached to a lifting beam.

The development of merchant ships demands cargo handling facilities for lifting increasingly heavy loads. If two booms or twin derricks and all their individual components are to be designed for handling such heavy loads, the entire equipment becomes heavy and cumbersome and it is increasingly unsuitable for handling loads individually with each boom. It is not therefore economical to design the two booms or derricks for handling very heavy loads, if they are primarily intended for handling lighter weight loads.

SUMMARY OF THE. INVENTION It is an object of the present invention to provide a hoisting gear which is well adapted to handling light as well as heavy loads according to requirements with a minimum expenditure in structural means.

According to the invention this object is achieved by the provision of an auxiliary luffing boom between two booms or derricks, and hoisting ropes which are taken from the booms or derricks over pulleys on a lifting beam to the head of the auxiliary luffing boom to which their ends are anchored.

When it is desired to lift twice the load that can be lifted by two cooperating booms or derricks the hooks and swivel blocks are removed and the ropes are attached to the head of the auxiliary boom. They are first each taken through a movable pulley block attached to the lifting beam carrying the hoist book. The heavy load is therefore suspended from a lifting beam as in a twin derrick and its weight is equally divided between the two pulley blocks. The load from the pulley blocks is again equally divided between the boom and the auxiliary luffing boom and it follows that each boom carries one quarter of the load plus the lifting beam, whereas the auxiliary luffing boom carries two quarters half the load.

The hoisting gear may be operated by designing the auxiliary luffing boom to extend roughly to the side of the ship. The booms or derricks are luffed from their maximum to their minimum radio radius of action. The load will then move about half the distance it would move if suspended from the booms or derricks individually. in calculating the stresses it must be remembered that the hoisting ropes exert their pull at an angle.

It the lufiing winch for the auxiliary boom is designed to handle the full moving load, the derricks and the auxiliary luffing boom may be luffed substantially simultaneously. This provides a favorable loading radius and stress distribution.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of example and with reference to the accompanying schematic drawing, in which:

FIG. 1 is a side elevational view of a twin boom derricking crane with an auxiliary boom in working position; and

FIG. 2 is a top plan view of a twin boom derricking crane and auxiliary boom.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 show a derricking crane with twin booms or derricks 3 and 4 luffed about horizontal pivot pins 5 into parallel position and capable of being slewed about vertical axles l and 2. An auxiliary luffing boom 6 can be luffed on a horizontal axle 10 and is sus ended from luffing ropes l7 and 18 which run over pulleys l and 20. With advantage the pulleys 19 and 20 are attached to a crossbeam 21 on a mast 24. The luffing ropes 17 and 18 are taken to a luffing winch not shown in the drawing.

The load is suspended from a lifting beam 14. Pulleys l5 and 16 are mounted on top of the lifting beam 14. Each of two hoisting ropes 22 and 23 runs from a winch, not shown, over pulleys 25 and 26 on the mast 24 to a pulley 27 at the boom head 11, back to a pulley 28 at the mast and then over a fixed pulley 29 on the boom head 11 back over one of the pulleys 15 and 16 to the head 7 of the auxiliary boom 6 where its end 8 or 9 is anchored.

The booms 3 and 4 of the derricking crane and the auxiliary luffing boom 6 may be rotatable about the common axis 12 of the mast 24. When not in use the auxiliary luffing boom 6 can be elevated into the vertical and also secured to the mast.

The two booms 3 and 4 each can each be independently luffed by a hydraulic cylinder 30 in a known manner.

FIG. 1 illustrates the transfer of a load 13 into a position 13' by luffing of the booms 3 and 4. The two booms 3 and 4 will then be in the positions indicated at 3 and 4'.

1 claim:

1. A hoisting gear for heavy loads, comprising a mast, a lifting beam having pulley means for carrying a load, a pair of twin booms pivotally attached to said mast for luffing and slewing and cooperating to hoist said lifting beam carrying a load, an auxiliary luffing boom pivotally mounted between said pair of booms, and hoisting ropes extending from said pair of booms through said pulley means of the lifting beam to the head of the auxiliary luffing boom whereby the weight of said load supported by said lifting beam is proportionally distributed between said twin and auxiliary booms.

2. A hoisting gear according to claim 1, wherein the two twin booms and the auxiliary luffing boom are arranged to be slewable about a common vertical axis.

3. A hoisting gear according to claim 2, further comprising a crossbeam with pulleys attached to said mast and a luffing winch, said auxiliary luffing boom being suspended from by luffing ropes extending through said pulleys on said crossbeam to said lufiing winch. 

1. A hoisting gear for heavy loads, comprising a mast, a lifting beam having pulley means for carrying a load, a pair of twin booms pivotally attached to said mast for luffing and slewing and cooperating to hoist said lifting beam carrying a load, an auxiliary luffing boom pivotally mounted between said pair of booms, and hoisting ropes extending from said pair of booms through said pulley means of the lifting beam to the head of the auxiliary luffing boom whereby the weight of said load supported by said lifting beam is proportionally distributed between said twin and auxiliary booms.
 2. A hoisting gear according to claim 1, wherein the two twin booms and the auxiliary luffing boom are arranged to be slewable about a common vertical axis.
 3. A hoisting gear according to claim 2, further comprising a crossbeam with pulleys attached to said mast and a luffing winch, said auxiliary luffing boom being suspended from by luffing ropes extending through said pulleys on said crossbeam to said luffing winch. 